PKGBUILD/pkg/sensor/bme280.go

package sensor

import (
	"context"
	"fmt"
	"log"
	"sync"
	"time"

	"github.com/d2r2/go-bsbmp"
	"github.com/d2r2/go-i2c"
	"github.com/d2r2/go-logger"
	"github.com/go-flucky/flucky/pkg/internal/format"
	"github.com/go-flucky/flucky/pkg/types"
	uuid "github.com/satori/go.uuid"
)

// BME280 is a sensor to measure humidity and temperature.
type BME280 struct {
	*types.Sensor
}

func (s *BME280) ID() string {
	return s.SensorID
}

// Read measured values
func (s *BME280) Read() ([]*types.MeasuredValue, error) {

	// Create new connection to i2c-bus on 1 line with address 0x76.
	// Use i2cdetect utility to find device address over the i2c-bus
	i2c, err := i2c.NewI2C(*s.I2CAddress, *s.I2CBus)

	if err != nil {
		log.Fatal(err)
	}
	defer i2c.Close()

	logger.ChangePackageLogLevel("i2c", logger.InfoLevel)

	sensor, err := bsbmp.NewBMP(bsbmp.BME280, i2c)
	if err != nil {
		log.Fatal(err)
	}

	logger.ChangePackageLogLevel("bsbmp", logger.InfoLevel)

	temperatureValue, err := sensor.ReadTemperatureC(bsbmp.ACCURACY_STANDARD)
	if err != nil {
		log.Fatal(err)
	}

	pressureValue, err := sensor.ReadPressurePa(bsbmp.ACCURACY_STANDARD)
	if err != nil {
		log.Fatal(err)
	}

	// pressureValueRound := math.Round(float64(pressureValue)/10*0.25) * 10 / 0.25

	_, humidityValue, err := sensor.ReadHumidityRH(bsbmp.ACCURACY_STANDARD)
	if err != nil {
		log.Fatal(err)
	}

	measuredValues := []*types.MeasuredValue{
		&types.MeasuredValue{
			ID:        uuid.NewV4().String(),
			Value:     float64(humidityValue),
			ValueType: types.MeasuredValueTypeHumidity,
			FromDate:  format.FormatedTime(),
			TillDate:  format.FormatedTime(),
			SensorID:  s.SensorID,
		},
		&types.MeasuredValue{
			ID:        uuid.NewV4().String(),
			Value:     float64(pressureValue),
			ValueType: types.MeasuredValueTypePressure,
			FromDate:  format.FormatedTime(),
			TillDate:  format.FormatedTime(),
			SensorID:  s.SensorID,
		},
		&types.MeasuredValue{
			ID:        uuid.NewV4().String(),
			Value:     float64(temperatureValue),
			ValueType: types.MeasuredValueTypeTemperature,
			FromDate:  format.FormatedTime(),
			TillDate:  format.FormatedTime(),
			SensorID:  s.SensorID,
		},
	}

	return measuredValues, nil
}

// ReadChannel reads the measured values from the sensor and writes them to a
// channel.
func (s *BME280) ReadChannel(measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error, wg *sync.WaitGroup) {
	if wg != nil {
		defer wg.Done()
	}

	measuredValues, err := s.Read()
	if err != nil {
		errorChannel <- err
		return
	}

	for _, measuredValue := range measuredValues {
		measuredValueChannel <- measuredValue
	}

}

// ReadContinously reads the measured values continously from the sensor and
// writes them to a channel.
func (s *BME280) ReadContinously(ctx context.Context, measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error) {
	for {
		select {
		case <-ctx.Done():
			errorChannel <- fmt.Errorf("%v: Context closed: %v", s.SensorName, ctx.Err())
			return
		default:
			s.ReadChannel(measuredValueChannel, errorChannel, nil)
		}
	}
}

// Ticker returns a new ticker, which tick every when the sensor should be read
func (s *BME280) Ticker() *time.Ticker {
	duration, err := time.ParseDuration(s.TickDuration)
	if err != nil {
		duration = time.Minute
	}
	return time.NewTicker(duration)
}